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820-3437 LD, after UC and jumpers OK(?) but no green light
- Thread starter george-a
- Start date
george-a
Member
ok I just had the guy bring me the LCD, there is also no backlight - are these related? or should I also find a new flat cable (tried DC board and magsafe is sound, original 85W)
BKL_EN, EDP_BKLT_EN, BKLT_PLT_RST_L are missing.
There is 8.5V output at the backlight fuse which means its not boosting but the FB trace is ok and I also replaced the driver L8550 (before I checked the Enable since there was corrosion there too).
BKL_EN, EDP_BKLT_EN, BKLT_PLT_RST_L are missing.
There is 8.5V output at the backlight fuse which means its not boosting but the FB trace is ok and I also replaced the driver L8550 (before I checked the Enable since there was corrosion there too).
ALB-Repairs
Member
Why are you measuring at the fuse? All that tells you is if the fuse is good or not, not that its not boosting. It sounds to me like the board may not be posting? Whats your LCD Enable voltage? Have you tried an external display?
Did you jump the resistor? was it meant to be 0Ohm?
Anyhow the way to tell if its not boosting is to check past the feedback, one of those big caps near the LVDS should show you your true backlight output voltage.
Did you jump the resistor? was it meant to be 0Ohm?
Anyhow the way to tell if its not boosting is to check past the feedback, one of those big caps near the LVDS should show you your true backlight output voltage.
george-a
Member
sorry you are right at the fuse I measured the expected voltage, at D7701 where I checked for continuity for the FB there is no output.
also the SMC_LID is HIGH.
the CPU although it gets 1V does not warm up.. it does but only a little...
ALB-Repairs
Member
u1950 id guess.